Atter shakedown and training in New England waters PC-487 departed New York 5 July and steamed in convoy via Norfolk, Key West, and the Panama Canal to the West coast. Arriving San Diego 10 August, she received ASW sound training, thence sailed 24 August for duty in the northwesteru sea frontier.

PC-487 arrived Seattle 4 September. During the next 5 months she operated on escort, patrol, and ASW missions out of' Puget Sound; and on 27 February 1843 she departed Seattle for similar duty along the Alaska Peninsula and among the Aleutians. She arrived Kodiak 4 March and sailed 2 days later via Dutch Harbor to Adak where she arrived 15 March to begin patrol and escort duty itor the Naval Auxiliary Air Facility.

Following the recapture of' Attu Island by American naval and ground forces 30 May, Adm. T. C. Kinkaid (Commander, North Paciffc Force) set up a destroyer blockade to isolate Japanese forces on Riska Island. Although Japanese surface ships under Vice Admiral Kawase successfully evacuated the island garrison 28 July, a plan to use blockade-running transport submarines for supply and evacuation missions proved disastrous.

Among those lost was I - . After completing one run to Kiska she was cruising at periscope depth north of' the Aleutians en route to Kiska. On the morning 10 June she encountered a three~ship American convoy; and in a "classaic antisubmarine battle" reminiscent of the Biblical battle between David and Goliath, the Japanese submarine fell victim to a gallant, aggressive submarine chaser, PC-487.

After departing Adak 8 June to escort LST-451 and Ute (AT-76) to the 8emichi Islands east ofAttu, PC-487 neared her destination, Shemya Island, early on 10 June. While steaming through heavy fog, she made sonar contact at 0800 and went to general quarter~ Three minutes later her radar detected a partially surfaced submarine, and at 0809 lookouta spotted two periscopes some 250 yards off the port bow. The spirited PC promptly increased speed 2rom 6 to 18 knots and attacked.

Turuing hard to port, PC-487 fired a spread off five depth charges which blew 18-9 to the surface. Completing her turn, the subchaser rammed 1-9 2rom the starboard "tearing both periscopes, antenna and net cutter" Blast" ing the sub's already damaged conning tower with 3-inch and 20mm. gunfire while turning, 4 minutes later the scrappy PC once again rammed the "almost completely surfaced" submarine. Steaming at 19.5 knots, she hit I-9 just forward of the conning tower. The ship `seemed to stick and pivot on top of the submarine and 2elt as though it would break in two"; but the force of impact rolled the doomed I-boat over and PC - 87 slid free across her deck.

The collision heavily damaged the subchaser's bow and hull, but she continued her attack with vigor, ffring at a range of 100 yards. Four projectiles trom her 3 inch guns hit the sub at her waterline, and a fifth struck her conning tower. The stricken enemy ship sank stern first at 0824 without firing a shot and plunged with all hands into 2,200 fathoms.

With forward compartments flooded and heavily dov,n by the bow, PC-487 proceeded to Massacre Bay, Attu, for emergency repairs. On 13 June she sailed in convoy for Adak, where Black lHawk (A`9) made additional repairs to her battered hull. Steaming via Dutch Harbor 29 June, the subchaser proudly returned to Seattle 9 July for 2 months of overhaul and extensive repairs.

During the entire war only three submarine chasers scored confirmed unassisted kills on enemy submarines. PC-487 made the only solo kill against a Japanese submarine. PC-565 and PC-624 attacked and sank German U-boats in the Atlantic and the Mediterranean, respectively, but neither was as spectacular as PC-487's furious encounted with I-9.

After completing battle repairs, PC-487 returned to Alaskan waters 11 September and resumed patrol and escort missions out of Dutch Harbor. On 27 November she sailed in convoy 2Or the Hawaiian Islands where during the remainder of the war she performed similar duty out of Pearl Harbor. Following the Japanese surrender, she remained in Hawaiian waters until sailing for the west coast 20 April 1946. She reached San Pedro, CA, the 28th; thence, on 3 May she departed for the east coast as escort for LSM-281. She reached Charleston, S.C., 22 May and remained there until 6 August when she steamed to Norfolk.

PC-487 decommissioned at Portsmouth, Va., 24 January 1947 and entered the Atlantic Fteserve Fleet. Whlle berthed at Norfolk, she was named Larchmont 15 February 1956. Her name was struck from the Navy list 1 July 1960.